The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Green snap is a weather-induced breaking of the corn stalk below the primary ear node (Wilhelm, et al., 1999). Snapping typically occurs during the five to eight leaf and/or the twelve leaf to tasseling stages of corn growth. These periods of increased susceptibility are due to the rapid rate of internode elongation. Generally, green snap is localized to a small area or a particular hybrid within a field. However, green snap has the potential to cause millions of dollars in damage to crops over wide areas. For example, on Jul. 8, 1993 a devastating storm caused an estimated $200 million of damage to Nebraska crops (Benson, 2001; Wilhelm et. al., 1999).
Strategies for protecting against green snap have included late planting, exclusion of growth regulator herbicides, suboptimal nitrogen rates, and monoculture (Wilhelm, et. al., 1999). While these strategies have demonstrated potential to protect against green snap, each strategy has resulted in limiting overall yield. Therefore, these methods are not effective or economical for large-scale protection against green snap damage.
Many industry professionals have suggested that in-seed protection is the best way to offer resistance to green snap. In general, strong, deep-rooted hybrids will suffer more than flexible, shallowly rooted hybrids from fast, damaging winds. Levels of lignin production and timing also play a role in green snap resistance. During rapid growth stages, lignin production cannot keep up with the rapidly elongating corn stalk, which compromises the stability and strength of the plant. In-seed breading of these traits can provide protection against green snapping.
Similarly, stalk lodging is the weather-induced breaking of the stalk below the ear. Stalk lodging results in increased harvest losses, slower harvest equipment speeds, increased drying cost and, in most cases, a significant volunteer problem next season. Yield losses from stalk lodging can range from five to twenty-five percent nationwide. Three main causes of stalk lodging are late season severe weather, damage to the stalk by the European corn borer and the stalk rot disease complex. The incidence and severity of stalk rot in any field will depend on the genetic susceptibility of the hybrid, the presence and virulence of the stalk rot organisms and the environmental conditions during the growing season. Almost all stress factors during the growing season can predispose the corn plant to invasion by stalk rot fungi. Management systems to reduce stress in the field include proper hybrid selection, proper plant population, adequate moisture at critical times, full fertility programs, insect control, crop rotation and timely scouting.